Field of the Invention
The present invention relates to a load control system, and more particularly, it relates to a load control system including a controller.
Description of the Background Art
A load control system including a controller is known in general. Such a load control system is disclosed in Japanese Patent No. 5877312.
Japanese Patent No. 5877312 discloses a motor control system including a motor controller. In this motor control system, a parameter (a position loop gain, a speed loop gain, or the like) for controlling a motor is stored in advance at the time of factory shipment of the motor controller. Furthermore, at the time of factory shipment, access to the motor controller (reading of the parameter, setting of the parameter, etc.) is prohibited.
To allow access to the motor controller, the parameter for controlling the motor is first transmitted from an external device to the motor controller. Then, access to the motor controller is allowed when it has been confirmed in the motor controller that the parameter stored in the motor controller is identical to the parameter transmitted from the external device. In other words, the parameter stored at the time of factory shipment of the motor controller is a password for allowing access to the motor controller. The parameter is set individually for the motor controller (vary from one motor controller to another), and hence even when the password leaks, a plurality of motor controllers cannot be accessed unlike the case where the plurality of motor controllers can be accessed with one password.
Although the parameter, which serves as the password, is set individually for the motor controller in the motor control system according to Japanese Patent No. 5877312, the motor controller that corresponds to the password can be accessed when the password leaks. Thus, there is such a disadvantage that functions (unique circuit functions of the apparatuses, for example) contained in the motor controller and an apparatus controlled by the motor controller leak, for example. In other words, there is such a problem that when a password for one of a plurality of apparatuses leaks, the function of another apparatus cannot be kept confidential.